On-Farm Establishment of Organic Birdsfoot Trefoil Pastures in the Northern Mountain West.

Pasture based dairy production presents a number of challenges when compared to confined feeding operations, including reduced milk production, increased enteric methane production, and the threat of forage-related health problems such as bloat.  Lotus corniculatus, commonly known as birdsfoot trefoil (BFT), is a high quality, non-bloating forage legume that has been found to increase milk production and reduce the production of enteric methane relative to other forages.  Although it is not persistent in the Midwest, BFT is persistent in cool, dry western climates, where it is well suited to irrigated pastures for ruminant production.  As part of a larger study comparing BFT to grass pasture systems, we are tracking the establishment of BFT pastures on five organic dairy farms in northern Utah and southern Idaho.  Participating producers cultivated pastures in the autumn of 2010, grew a crop of oats in 2011, cultivated and seeded BFT pastures at 25 kg/ha (22.3 lb/acre) pure live seed in between 26 July and 8 September 2011.  First emergence of BFT was observed approximately one week after irrigation or rainfall.  BFT and weed densities were systematically sampled 17-23 days after first BFT emergence.  A map of each field was created using ArcGIS (ESRI, Redlands, CA) with a superimposed grid of 30.5 m² blocks to facilitate systematic sampling. Among the five participating farms, weed density was significantly lower than BFT density on three.  On the remaining two, BFT and weed densities were not significantly different. On all farms BFT seedling density was high, averaging 715 plants/m² (67 plants/ft²).  In the spring of 2012, BFT and weed densities will be measured again for comparison, and dry matter production and forage nutritive value will be measured as the season progresses.